Conventional leadless housings, such as TSLP (thin small leadless package) housings, are typically singulated via a separation by grinding process. For this purpose, a metallic carrier on which a plurality of semiconductor devices and wiring structures are arranged on a common plate comprising a plastic housing composition is first etched away chemically, so that the wiring structures are uncovered and are freely accessible. As a result, corresponding metallic contact areas of the wiring structures can be coated to form external contact areas or can have external contacts fitted to them.
A plurality of the semiconductor devices are embedded into a common plastic composition under the common so-called “mold cap”, which is called composite board hereinafter. The composite board unites the wide variety of components of the semiconductor devices, such as semiconductor chips, connecting elements, external contact areas, etc., in a plate-type plastic body which, after the external contact areas have been fitted thereto, is subsequently separated into individual surface-mountable semiconductor devices via a sawing technique. For this purpose, the composite board is adhesively bonded on to a sawing film and the semiconductor devices are subsequently singulated on the sawing film via a wafer saw. After singulation, the semiconductor devices are arranged on the sawing film in such a way that they can be tested with regard to their functionality via the external contact areas or the external contacts before they are removed from the sawing film and packaged into corresponding transport belts.
This method has the disadvantage that the known separating by grinding processes for singulating the semiconductor devices are complex in terms of process engineering on account of the high loading of the plastic housings and the wear of the saw blades during these manufacturing operations. One reason for the failure rate after the separating by grinding can be seen in the fact that not only is the metallic carrier ground away, but also the adjoining wiring structure can be detrimentally affected.